The bath is no longer a bowl of anxiety. It is once again a threshold—a place to enter and leave freely. Until next month, when the biofilm begins its patient reconstruction.

Sodium hydroxide (lye) generates intense heat. In a standing bath, that heat dissipates into the three inches of stagnant water above the blockage, rendering the chemical inert before it ever reaches the plug. You have effectively heated your bathwater, not cleared the pipe.

You pull the plug. Instead of the satisfying gurgle-chug of a vortex draining to the void, you get hesitation. A lag. The water rises around your ankles like a slow-motion tide of failure. You stand, shivering, watching the meniscus refuse to fall. The bath has become a bowl. You are trapped in a lukewarm mausoleum of your own dead skin cells. To understand the blocked bath, one must understand the trinity of sludge that conspires against modern plumbing.

Furthermore, chemical drain cleaners create a "glassification" effect. The heat melts the surface of the PVC pipe slightly, and the chemical reaction leaves behind a smooth, calcified glaze that actually narrows the diameter of the pipe for future blockages. The truth arrives in the form of the Plumber’s Snake (or the Zip-It tool).